The problem of allowing users to adjust the height of the upper extractable rack within the washing compartment of the machine, e.g. to be able to allow dishes of different height to be inserted (e.g. plates of different diameter or tumblers and wine glasses) into the dishwasher rack, thus always optimizing the available space, is particularly felt in the dishwasher industry. For example, an adjustment device is known from EP0033483; it is based on side supporting members for the rack, normally engaging the fixed guides of the dishwasher, provided with two upper and lower parts reciprocally and vertically sliding, which may be fixed at different heights by means of disconnectable blocking portions thereof.
Such a device however has relatively complex structure and operation, and may thus cause jamming; furthermore, it is in any case costly, large in size and relatively complex to be used by the user. Moreover, the above-described device is not adapted to be used in other applications, e.g. for adjusting the position of the inner supporting shelves of a refrigerator or freezer in height, where today the need to allow the user to make this adjustment in a simple and rapid manner and with small volumes, is also very felt, in order to allow, even in this case, the stowage of food of different size into the inner volume of the electric household appliance to be optimized.